Add the potatoes to a large bowl and toss with melted butter. Mix in the oregano, garlic powder, salt, pepper and ¼ cup grated parmesan. Toss until the potatoes are fully coated.
Grease your air fryer basket with spray oil and add the potatoes cut side down in a single layer. (See note #1 below).
Air fry on 380F for 15 minutes, then carefully flip the potatoes over, sprinkle on the remaining ¼ cup parmesan cheese and air fry for another 5-7 minutes, or until the potatoes are golden brown and fork tender.
Notes
Air fry in a single layer. For the best results, you'll want to air fry the potatoes cut side down in a single layer. Depending on the size of your air fryer, this may mean air frying the potatoes in two batches or you can half the recipe.
Size of potatoes. Make sure your baby potatoes are all roughly the same size so they cook evenly and at the same rate. Larger potato pieces will take longer to cook.
Pat potatoes dry. If you're not using pre-washed potatoes, rinse them first and scrub clean (if necessary) and then pat them dry before tossing with melted butter and seasonings.